Error: This installation package could not be opened
When trying to install the ArcWeb Toolbar, the following error message appears:
"This installation package could not be opened. Verify that the package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer package."
You may see this error if you attempt to install the ArcWeb Toolbar while connected to the Internet using an authenticating proxy server.
Solution or Workaround
If you connect to the Internet using an authenticating proxy server, you need to run a modified install program to install the ArcWeb Toolbar.
Download the installation .zip file from the ArcWeb Toolbar Download page.
The .zip file contains a separate installation that lets you install the software while connected to the Internet using an authenticating proxy server. Extract the contents of the file to a directory on your machine. Included in the contents of the .zip file is a file called Setup.exe. Double click this file and proceed with the installation.